package com.hmdp.utils;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.hmdp.entity.Shop;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;

import static com.hmdp.utils.RedisConstants.*;

@Component
public class CacheClient {
    private final StringRedisTemplate stringRedisTemplate;

    public CacheClient(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    public void set(String key, Object value, Long time, TimeUnit unit){
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(value), time, unit);
    }

    public void setWithLogicalExpire(String key, Object value, Long time, TimeUnit unit){
        RedisData redisData = new RedisData();
        redisData.setData(value);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(unit.toSeconds(time)));
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(redisData));
    }

    public <R,ID> R queryWithPassThrough(String keyPrefix, ID id, Class<R> type, Function<ID,R> function,Long time, TimeUnit unit){
        String key = keyPrefix + id;
        //1、从redis查询商铺缓存
        String stringJson = stringRedisTemplate.opsForValue().get(key);

        //2、判断是否存在
        if(StrUtil.isNotBlank(stringJson)){
            //3、存在，直接返回
            return JSONUtil.toBean(stringJson, type);
        }
        if(stringJson != null){
            return null;
        }

        //4、不存在，根据id查询数据库
        R r = function.apply(id);

        //5、不存在，返回错误
        if(r == null){
            //将空值写入缓存
            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
            return null;
        }

        //6、存在，写入redis
        this.set(key, r, time, unit);
        //7、返回
        return r;
    }
}
